Office workplace injuries, such as carpal tunnel syndrome, muscle fatigue and back injuries, have dramatically increased over the past several years. New medical terminology for such injuries include Repetitive Motion Injury (RMI), Cumulative Trauma Disease (CTD) and Overuse Syndrome (OS) among others. It is widely accepted that such increase in workplace injuries is a result of information age workers being force to work in a sedentary, constrained position for extended time periods performing highly repetitive tasks. Such injuries are further exacerbated by ergonomically improper working positions.
Costs of worker's compensation claims, lost time, retraining, job reassignment and permanent disability claims associated with such injuries have skyrocketed. Repetitive motion activities performed over an indeterminate period of time (i.e., many years for some operators, a few weeks or months for others) coupled with improper static working posture, inadequate breaks and/or poor working environment are believed to be the cause of nearly 50% of all RMI worker's compensation claims.
Attempts have been made to alleviate the above-noted problems. Many organizations, including the federal government, have instigated policies for reducing the amount of continuous time spent performing repetitive-type motions. For example, many workers are given frequent breaks (e.g., hourly) to allow them to break up the repetitive tasks into shorter segments. Other concepts include job sharing, part-time workers, shorter shifts, and work station rotation.
The above-noted attempts to solve the problems of RMI-type injuries are impractical and/or inefficient in many working situations. Further, none of the above-noted concepts addresses one of the roots of the problem; that is, improper interface between worker and work station. In fact, some of the concepts (e.g., job sharing and work station rotation) may actually exacerbate the problem by rotating workers (e.g., of different physical dimensions) through a single work station which is set up to accommodate the physical dimensions of only a single worker.
As noted above, one of the causes of RMI-type injuries is improper static working position (e.g., improper positioning of the worker relative to his/her work surface, such as a desk or table). Desk and table design has traditionally revolved around the anthropometric requirements of the 95th percentile male user (i.e., about 6' 2" tall) in order to "fit" the widest range of potential users. As a result, most users are forced to work in a position that is not the optimum (i.e., is too high) from a comfort, health and safety standpoint for their own particular physical dimensions, thereby causing the above-noted types of injuries. Further, although allowing a worker to change from a sitting to a standing position has been found to decrease workplace injuries, few desks are designed to allow a worker to stand while working.
Some attempts have been made to design work surfaces which are adjustable in height, thereby allowing modification to fit a range of worker dimensions and/or allowing workers to stand while working. However, many of these designs do not adequately accommodate a range of users from small females to large males. For example, to meet the adjustment range required to serve the 5th percentile sitting female (about 4'11" tall) and the 95th percentile standing male (about 6'2" tall), the work surface height must range from about 25 inches to about 46 inches. Many known designs cannot achieve the above-noted requirement without significant sacrifice of table rigidity due to inadequate extension member support when fully extended. Further, many of the known designs are not easily adjustable, and therefore are sometimes not utilized to their full extent because of the hassle in performing the adjustment procedure.
Accordingly, it is an object of the present invention to design a support assembly, such as a table, desk or chair, that can be easily adjusted to vary the height of the support surface, such as a table top, desk top or chair seat.
Another object of the present invention is to design a support assembly that can be adjusted in height from 25 inches to 46 inches without significant loss of extension member rigidity.
Still another object of the present invention is to design an automatically adjustable support assembly that will automatically move to a selected position by setting a control (e.g., a dial).
It is yet another object of the present invention to design an automatically adjustable support assembly that automatically stops height adjustment (e.g., in the downward direction) if an obstacle is in the way.
It is a further object of the present invention to design an adjustable support assembly requiring substantially no bulky supporting structure or cross braces which may interfere with knee space or obstruct the area required for free movement of the user's legs under the support surface.